THE EFFECTS OF POSITIVE AND NEGATIVE EXPERIENCES ON SUBSEQUENT BEHAVIOR AND COGNITION IN CAPTIVE CAPUCHIN MONKEYS (CEBUS APELLA)

While it is known that acute and chronic stress can impact cognition in a range of species, less is known about the immediate impacts of minor frustration or positive experiences on subsequent behavior and cognition in a primate model. The current study used a novel methodology to engineer both positive and (slightly) frustrating experiences, using the same apparatus, in 15 adult capuchin monkeys. After the positive or negative experience (or a control condition with no manipulation), subjects were presented with a delayed match-to-sample (DMTS) task for 30 minutes to assess working memory (6 sessions for each condition). As predicted, experiencing a frustrating task prior to testing resulted in a decrease in performance on the DMTS compared to after a positive experience (LMM: b=0.02, SE=0.01, z=2.80, p=.015) or the control (b=0.03, SE=0.01, z=3.32, p=.003). However, contrary to predictions, a positive experience did not facilitate performance to higher levels than the control condition. Additionally, behavioral analysis indicated increased levels of scratching, commonly used as an indicator of stress, after the negative experience compared to both the positive experience (GLMM: b=-0.08, SE=0.03, z=-3.04, p=.002) and the control (b=-0.09, SE=0.03, z=-3.10, p=.002), but no difference between positive and control conditions. These results indicate that negative experiences, even minimally frustrating ones, impact subsequent behavior and cognition in primates, but that there may not be an enhancing effect of positive experiences.